A conventional display device is, for example, ahead-up display device disclosed in PTL 1. This device projects display light from a display unit onto a windshield of a vehicle, thereby displaying a virtual image of an image formed by the display light. This device is configured so that the display light from the display unit is reflected by a concave mirror to be directed toward the windshield and is also configured so that a display position of the virtual image can be adjusted by rotationally moving the concave mirror by using a stepping motor.
In the case where the stepping motor is used as described above, it is necessary to perform return-to-home operation for returning the stepping motor to a mechanical reference position at the time of, for example, starting the device and then determine a home position. In the device of PTL 1, a home position (reference position) of the concave mirror is determined by bringing the concave mirror into contact with a mechanical switch (limit switch).